Self-releasing and self-lowering block

ABSTRACT

A self-releasing, self-lowering block adapted to rest upon a horizontal support cable. A vertically extending hoisting cable extends about the support cable, through sheaves in the block, and is retained within pivoted sections of the block. A release element attached to the hoisting cable can be raised to effect release of the pivoted sections so that they may move apart and allow the block to drop off the support cable and slide down the hoisting cable. Certain ones of the sheaves of the block are laterally offset to impart a drag upon the block and slow its descent.

llnited States Patent [191 Bagby 1 SELF-RELEASING AND SELF-LOWERINGBLOCK [76] Inventor: Percy R. Bagby, 27844 Conestoga Dr., Rolling Hills,Calif. 90274 22 Filed: Aug. 24, 1972 [21] App]. No.: 283,394

[52] U.S. Cl 254/190, 254/192, 254/196, 254/197, 24/132, 294/83 [51]Int. Cl B66d 1/28, B66d 5/32 [58] Field of Search 254/190 R, 192, 193,197, 194, 254/195, 196; 294/83 R; 24/132 R 3/1959 Livingston 254/197X 1Jan. 22, 1974 610,172 9/1898 Dotson 254/193 Primary Examiner-Richard E.Aegerter Assistant Examiner-Jeffrey V. Nase [57] ABSTRACT Aself-releasing, self-lowering block adapted to rest upon a horizontalsupport cable. A vertically extending hoisting cable extends about thesupport cable, through sheaves in the block, and is retained withinpivoted sections of the block. A release element attached to thehoisting cable can be 'raised to effect release of the pivoted sectionsso that they may move apart and allow the block to drop off the supportcable and slide down the hoisting cable. Certain ones of the sheaves ofthe block are laterally offset to impart a drag upon the block andslowits descent.

6 Claims, 9 Drawing Figures PAIENTED JAN 2 2 I974 SHEEY 1 BF 2 FIGW5SELF-RELEASING AND SELF-'LOWERING BLOCK BACKGROUND OF THE INVENTION l.Field of the Invention The present invention relates to aself-releasing, selflowering block, and more particularly to such ablock which is releasable by means of a release element attachable to acable trained through the block.

2. Description of the Prior Art I There are many situations in which itis necessary to support men and material for work upon cable mountedequipment or the like located at relatively great heights and inrelatively inaccessible positions. One method utilizes a block which isattached to the cable which mounts the equipment. A hoisting cabletrained through the block is then used to raise an equipment cab or thelike carrying the men and their working materials. Once the work iscompleted the equipment cab is easily lowered to-the ground, butdetachment of the block from the support cable is difficult. Preferablythe block should be remotely actuable to drop off the support cable, andits rate of descent should be at a controlled rate to avoid injuringpersonnel and damaging the block. Various devices have been advanced inthe prior art to accomplish these goals, but none have been entirelysatisfactory.

SUMMARY According to the present invention, a block is provided whichcomprises a pair of hinged sections of generally U-shape adapted to restupon a support cable. The block sections include a plurality of sheavesabout which a hoisting cable can be trained. The hinged block sectionsare held together in closed position by a releas able arm underlying thesupport cable. However, upon attachment of a release element to thehoisting cable, and hoisting of the release element into engagement withthe release arm the block sections are allowed to be pivoted apart bythe continued pulling of the hoisting cable. The outwardly pivoted blocksections are thus pulled over and slide off the support cable.

Certain ones of the sheaves on the block sections are laterally offsetin the release position of the block to form a loop in the hoistingcable, and thereby impose a drag to slow the descent of the block to theground. Once the block has reached the ground, the hoisting cable needonly be opened to form a free end which" can be pulled over the supportcable. 1

Other objects and features of the invention will become apparent fromconsideration of the following description taken in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of ablock according to the present invention;

FIG. 2 is a longitudinal cross-sectional view of the block of FIG. 1,the release arm being shown in its latched position;

FIG. 3 is a view similar to FIG. 2, but illustrating the release armbeing moved toward its release position;

FIG. 4 is an enlarged view taken along the line 4-4 of FIG. 3;

FIG. 5 is an enlarged view taken along the line 5-5 of FIG. 1;

FIG. 6 is an elevational view of the block of FIG. I, with the releaseam being located in the position illustrated in FIG. 3;

FIG. 7 is a view similar to FIG. 6, but illustrating the release arm inits fully released position, with the block sections pivoted fartherapart;

FIG. 8 is a view similar to FIG. '7, but illustrating the block sectionspivoted almost completely apart, and further illustrating the supportcable just prior to disengagement of the block therefrom; and

FIG. 9 is a view similar to FIG. 8, but illustrating the block releasedfrom the support cable and descending toward the ground at a slowedrate.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,there is illustrated a self-releasing, self-lowering block 10 accordingto the present invention and comprising, generally, a main block section12 of inverted U-shape having a longer leg on one side, and a secondaryblock section 14 constituting a downward continuation of the oppositeshort side of the main block section 12. The section 12 includes a pairof spaced apart pivot brackets 16 which support a pintle 18, whereby thesections 12 and 14 are pivotable relative to one another from the closedposition illustrated in FIG. 2 to the open position illustrated in FIG.9.

The block 10in the particular application described herein is adaptedfor disposition upon a horizontally oriented support-cable 20, the cable20 extending through the U-shaped support passage or central openingdefined by the block sections 12 and 14 in their closed position.

The block 10 is utilized to raise and lower men and equipment from theground to the elevated position of the support cable 20 for working uponcable mounted fittings or equipment such as insulators, where the cable20 constitutes part of alarge antenna for example.

A cab (not shown) carrying the men and equipment is attached to ahoisting cable 22 which is disposed through the block 10. As will beseen, the hoisting cable 22 also forms a partof the mechanism foreffecting the spreading apart movement of the block sections 12 and 14toward their release position.

The main block section 12 is formed by a pair of side plates 24 and 26secured-together and maintained in spaced apart relation by a pluralityof nut and bolt assemblies 28 located adjacent the upper outer marginsof the plates 24 and 26. The plates 24 and 26 each include an integral,axially outwardly extending flange 30. In addition, an arcuatereinforcing member 32 of inverted U-shape is welded to the undersides ofthe flanges 30, extending axially of the block 10 parallel to the axisof the support cable 20'. A U-shape member 34 made of rubber is adheredto the adjacent surfaces of the member 32 and flange 30,the resilientwearing surface of the member 34 beingadapted to engage the supportcable 20 without damage to the cable.

As best viewed in FIG. 2, the right leg of the U-shape member. 34 islonger and slotted at 38 to receive a release arm 48, as will be seen.The slot 38 is in communication with the open area between the spacedside plates 24 and 26 of the main block section 12.

A pair of side plates 40 and 42 are pivotally mounted to the pintle 18and appear to be downward extensions of the left sides of the plates 24and 26. However, the place where the plates 40 and 42 abut against theplates 24 and 26 constitutes the hinge joint of the block in its closedposition.

The pivot brackets 16 supporting the pintle 18 are welded to the mainblock side plates 24 and 26, as best illustrated in FIG. 1.

The side plates 40 and 42 include flanges 44 located opposite theslotted leg 36, and one of these flanges 44 is provided with a slot 46,as best seen in FIG. 2, to enable the release arm 48 to extendtherethrough.

' the release arm 48 is located below the support cable 20, and extendsacross the central opening defined between the block sections 12 and 14in their closed position, as best seen in FIG. 2. The arm 48 ispivotedly supported at one extremity by a pivot pin 50 which is carriedby the secondary block side plates 40 and 42. The opposite, freeextremity of the release arm 48 is biased downwardly by a torsion spring52 disposed upon the pivot pin 50. One extremity of the spring 52 isengaged upon the upper margin of the arm 48, and the other extremity isengaged upon an abutment or pin 54 carried by the secondary blocksection 14. The free extremity of the release arm 48 is downwardlyoffset to form a latch portion 56 which is disposed through a slot orlocking detent 58 in the side plate flange 30, and also extends into thespace between the side plates 24 and 26.

In operation, the release arm 48 is pivotable upon the pin 50, andnormally has the latch portion 56 thereof in engagement with the lowermargin of the locking detent 58. This prevents the block sections 12 and14 from pivoting outwardly about the axis of the pintle 18.

A vertically extending release pin 60 located in the space between theplates 24 and 26 is carried for vertical slidable movement by a pair ofvertically spaced trunnions 62 which are attached to the adjacentsurface of the flange 30. The upper end of the pin 60 is provided with aflattened end or head adapted to engage the lower end of the latchportion 56 to raise it when the opposite or lower end of the pin 60 isengaged by a release element 64, as will be described subsequently.

The hoisting cable 22 is trained upwardly between the main block sideplates 24 and 26, between a pair of confronting pulleys or sheaves 66,then around three sheaves 68 at the top of the block 10, and thendownwardly between the plates 40 and 42 and between a pair ofconfronting sheaves 70. All of the sheaves 66, 68, and 70 rotate aboutaxes generally parallel to the axes of support cable and pintle l8, andsupport and guide the cable 20 through the block 10.

In a typical operation in which, for example, the support cable 20 is alarge antenna, and work has to be done on insulators (not shown) carriedby the antenna, the block 10 is first mounted at one end of the cable.The block is then moved down the cable to the proper location with thehoisting cable 22 in position. Next, the cable 22 is used to hoist themen and equipment to the work site.

Once the work is completed, the hoisting cable 22 .is operated to lowerthe men and equipment to the ground. The release element 64 is thenattached to the cable 22. It constitutes an enlargement or obstructionfor actuating the release pin 60 and can be formed by any suitablemeans. As best seen in FIG, 5, the element 64 of the present embodimentcomprises a pair of semicylindrical portions 72 and 74 having integralsleeve half-sections 76 and 78 which together define a central,vertically oriented passage 80 to receive the cable 22. A pair of nutand bolt assemblies 82 are provided to securely clamp the half-sections76 and 78 onto the hoisting cable 22, as will be apparent.

After the release element 64 is attached to the cable 22, the cable 22is used to hoist the release element 64 until it abuts against theheaded lower end of the release end 60 and moves it upwardly, as seen inFIG. 3. Continued pulling upon the cable 22 causes the release element64 to upwardly move the pin 60, which in turn moves the latch portion 56into alignment with the locking 58. In addition, the continued pullingtends to push up the main block section 12 about the pintle 18. Thiscauses the locking detent 58 to move outwardly of the latch portion 56,enabling the bias of the spring 52 to urge the release arm 48 toits-most downward position, as seen in FIG. 7. FIG. 7 also illustratesthe continued upward and outward pivoting of the main block section 12in response to continued downward pulling upon the opposite run of thehoisting cable 22.

FIG. 8 shows the pivoted position of the main block section 12 justprior to the time that the orientation of the block sections relative tothe cable 20 allows the block 10 to-fall off the cable 20. Once theblock 10 has dropped off the cable 20, as seen in FIG. 9, the onlyconstraint preventing the block 10 from plummeting to the ground is thedrag imposed on the cable 22 by the engagement thereof by the sheaves66, 68 and 70. Certain ones of these sheaves are laterally offsetrelative to the others, as seen in FIG. 9, so that a bight or loop isformed in the cable 22 sufficient to develop a drag that slows theotherwise rapid descent of the block 10 to the ground.

To complete the operation, the hoisting cable loop is opened-at somepoint to provide a free end which can be pulled over and free of thesupport cable 20.

From the foregoing it is seen that the block 10 is selfreleasing, byoperation of the release element 64 upon the release pin 60, andself-lowering, by reason of the frictional drag imparted by the presenceand location of the sheaves 66, 68 and 70.

Various modifications and changes may be made with regard to theforegoing detailed description without departing from the spirit of theinvention. It will be apparent that recitation of the support cable 20is merely exemplary, and that the block 10 is adapted for similaroperation with respect to any element disposed through the blockopening. In addition, the term cable" as used herein is intended tocomprehend analagons lines, such as ropes, chains and the like.

I claim:

1. A self-releasing, self-lowering block for mounting upon a cabledisposed over a support member, said block comprising:

first and second block 'sections defining a downwardly opening supportpassage, said first block section being disposed upon one vertical runof a cable, said second blockvsection being mounted to said first blocksection for upward pivotal movement from a closed position in which saidsupport passage opens downwardly and an open position in which saidsupport passage opens upwardly whereby, upon location of a cable meansin said support passage, said block sections are supported by such cablemeans in said closed position, and whereby said block sections drop offsaid cable means in said open position, said block sections includingsheaves adjacent said support passage for training a cable up one sideof said support passage, over said support passage, and down the otherside of said support passage, certain of said sheaves on said firstblock section being laterally offset in said open position relative tocertain of said sheaves on said second block section whereby a cabletrained through said sheaves does not lie in a straight line in saidopen position; and

release means including an arm disposed across said support passage insaid closed position, said arm being selectively operable for' movementaway from said support passage.

2. A self-releasing, self-lowering block according to claim 1 whereinsaid sheaves include a pair of oppositely disposed sheaves in the lowerextremity of said second block section whereby forcible engagement ofsaid second block section by an obstruction on a'cable trained throughsaid oppositely disposed sheaves tends to pivot said second blocksection toward said open po sition. v

3. A self-releasing, self-lowering block according to claim 1 whereinsaid release arm is pivotally mounted to one of said block sections andprojects at its free extremity into locking engagement with the other ofsaid block sections, said release means including a release pin normallyout of engagement with said release arm, but movable into engagementwith said release arm upon engagement of said release pin by an releaseelement on a cable trained through'said sheaves whereby said release armis pivoted out of said locking engagement.

4. A self-releasing, self-lowering block according to claim 1 whereinsaid release means includes bias means engaged upon said release arm andtending to pivot said release arm out of said locking engagement.

5. In combination with a hoisting cable disposed up and over a generallyhorizontally oriented cable means,

a self-releasing, self-lowering block comprising:

first and second block sections assembled to define an inverted U-shapestructure having a downwardly opening support passage through which saidcable means extends to support said block sections, said first blocksection being disposed upon one vertical run of said cable, said secondblock section being mounted to said first block section for upwardpivotal movement from a closed position in which said support passageopens downwardly and an open position in which said support passageopens upwardly whereby said block sections are enabled to drop off saidcable means, one of said block sections including a locking detent, saidblock sections including sheaves adjacent said support passage fortraining a hoisting cable up one side of said support passage, over saidsupport passage, and down the other side of said support passage,certain of said sheaves on said first block section being laterallyoffset in said open position relative to certain of said sheaves on saidsecond block section whereby the hoisting cable does not lie in astraight line in said open position; and

a release arm pivotally carried by one of said block sections andnormally'projecting across said sup; port passage in said closedposition and in engaged relation with said detent; and

a release pin carried by one of said block sections and actuable by anrelease element on said cable to pivot said release pin out of saidengaged relation with said detent whereby said second block section isfreely pivotable toward said open position.

6. A self-releasing, self-lowering block according to claim 5 andincluding bias means engaged upon said release arm and tending to movesaid release arm away from said support passage when said release arm isout of said engaged relation-with said detent.

1. A self-releasing, self-lowering block for mounting upon a cabledisposed over a support member, said block comprising: first and secondblock sections defining a downwardly opening support passage, said firstblock section being disposed upon one vertical run of a cable, saidsecond block section being mounted to said first block section forupward pivotal movement from a closed position in which said supportpassage opens downwardly and an open position in which said supportpassage opens upwardly whereby, upon location of a cable means in saidsupport passage, said block sections are supported by such cable meansin said closed position, and whereby said block sections drop off saidcable means in said open position, said block sections including sheavesadjacent said support passage for training a cable up one side of saidsupport passage, over said support passage, and down the other side ofsaid support passage, certain of said sheaves on said first blocksection being laterally offset in said open position relative to certainof said sheaves on said second block section whereby a cable trainedthrough said sheaves does not lie in a straight line in said openposition; and release means including an arm disposed across saidsupport passage in said closed position, said arm being selectivelyoperable for movement away from said support passage.
 2. Aself-releasing, self-lowering block according to claim 1 wherein saidsheaves include a pair of oppositely disposed sheaves in the lowerextremity of said second block section whereby forcible engagement ofsaid second block section by an obstruction on a cable trained throughsaid oppositely disposed sheaves tends to pivot said second blocksection toward said open position.
 3. A self-releasing, self-loweringblock according to claim 1 wherein said release arm is pivotally mountedto one of said block sections and projects at its free extremity intolocking engagement with the other of said block sections, said releasemeans including a release pin normally out of engagement with saidrelease arm, but movable into engagement with said release arm uponengagement of said release pin by an release element on a cable trainedthrough said sheaves whereby said release arm is pivoted out of saidlocking engagement.
 4. A self-releasing, self-lowering block accordingto claim 1 wherein said release means includes bias means engaged uponsaid release arm and tending to pivot said release arm out of saidlocking engagement.
 5. In combination with a hoisting cable disposed upand over a generally horizontally oriented cable means, aself-releasing, self-lowering block comprising: first and second blocksections assembled to define an inverted U-shape structure having adownwardly opening support passage through which said cable meansextends to support said block sections, said first block section beingdisposed upon one vertical run of said cable, said second block sectionbeing mounted to said first block section for upward pivotal movementfrom a closed position in which said support passage opens downwardlyand an open position in which said support passage opens upwardlywhereby said block sections are enabled to drop off said cable means,one of said block sections including a locking detent, said blocksections including sheaves adjacent said support passage for training ahoisting cable up one side of said support passage, over said supportpassage, and down the other side of said support passage, certain ofsaid sheaves on said first block section being laterally offset in saidopen position relative to certain of said sheaves on said second blocksection whereby the hoisting cable does not lie in a straight line insaid open position; and a release arm pivotally carried by one of saidblock sections and normally projecting across said support passage insaid closed position and in engaged relation with said detent; and arelease pin carried by one of said block sections and actuable by anrelease element on said cable to pivot said release pin out of saidengaged relation with said detent whereby said second block section isfreely pivotable toward said open position.
 6. A self-releasing,self-lowering block according to claim 5 and including bias meansengaged upon said release arm and tending to move said release arm awayfrom said support passage when said release arm is out of said engagedrelation with said detent.